Split batch, one carboy is further along than the other

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zacster

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I made a lager last weekend, 5.5 gallons, that I split between 2 3g Better Bottle carboys so they fit in my fridge. I first let the wort settle in a single glass carboy, then split it by siphoning. The first carboy got all clear wort since I held the siphon up midway and the second got some of the trub. I had made a 2L starter too, and it had settled to a hard cake at the bottom of the flask. I decanted about half or more of the clear liquid and then put it back on my stir plate to loosen it all up, and I made sure it was all loose. I let it stir while I retrieved the 2 bottles from the fridge, so it should've been pretty well stirred. I then looked at the measurement of what was left of the starter, about a liter, and split that by eye into the two carboys. I shook them both as always to oxygenate.

I put them in the fridge at 45, and only the cloudy one started the first day. I raised the temp to 47 and the other started to ferment as well. But when I took readings today, the cloudy one was at 1.020 and the clear one was still at 1.030. A taste test confirmed it, one tasted like beer and the other tasted like sweet barley water. Post boil gravity was 1.050, lower than I expected.

I'm thinking one of four things happened here to get such uneven results. First, obviously it could be I didn't split the yeast as evenly as I thought. Second, maybe I didn't shake one or the other as thoroughly. Third, when I siphoned, the sugar levels had settled and weren't even and when I siphoned from the top I didn't get even distribution. Fourth, the trub itself contributed to the fermentation and got it started.

When I took the post boil gravity it had already settled, so maybe taking that from the top gave me a lower reading? I'd never thought that before, and I don't think I did it any differently in the past.

What do you think and what should I do? I can always mix them together again and split it back up. It is too hot here to just put them back into the glass carboy and leave it. Or just leave it and let it continue to ferment as it is, and hope the other catches up? The fermentation is still active. I raised the temp to 49 in any case, maybe put it at 50?
 
The fermentation got stronger at 49, so I'll just let it go on. I'll pull the one out for a D-rest into the air conditioned room when it is ready, and then the other for that.
 
I think you're on the right track. There are approximately 1,005.27 variables that could affect fermentation rate, one batch lagging could be anything and likely doesn't indicate anything. Wort wants to turn into beer. Cheers!
 
I just checked it again and it is bubbling like crazy now with the temp still at 49. It won't take long. I'll check gravity again maybe tomorrow evening.
 
After another few days from my last post I had the gravity down below 1.020 in both, maybe 1.014 in one and 1.018 in the other. I set the controller up to 62F and let it bubble away for the D-rest. It is now at 1.012 but still a little sweet to taste. I'll leave it for a few more days and then crash it.

I'm hoping crashing it will settle out the yeast as it would be super clear if it did.

I still need to get CO2, but I should have everything else. I'll keg it and let it lager and carbonate for 2-3 weeks, but once the carbonation level is right it's really hard to not take "tastes".
 
Another try tonight and the sweetness is gone. Gravity was at 1.009, just between the gradations. I'm drinking the sample now and set the thermostat down to 3c. I'll turn it down a few more when it settles, not likely until tomorrow. It is somewhat hazy but it should clear up, the other carboy with the sediment is actually clear.
 
I did a second batch the same way a few weeks ago and this time they both tracked the same and both are clear. Who knows.
 
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